1. Field of the Invention
The present invention relates to a material classification device that removes relatively heavy solid material from a stream of fluid and solid material. The device is particularly suitable for the extraction of gold from alluvial material. The solid materials are generally removed from the beds of bodies of water but may also be removed from above the water line and placed in a stream of fluid. The device, being small and generally lightweight, is suitable for use by a single individual by either placing the apparatus on the ground or partially submerging it in a body of water.
2. Description of the Prior Art
Many devices have been used over the years to separate materials that have a relatively high specific gravity from lighter materials. Sluice boxes, similar to that disclosed by the patent to George Gates, U.S. Pat. No. 482,241, are well known. Many of these devices contain various sieving and screening apparatus for classification of materials.
Frequently dredges are used to vacuum up material from the bottoms of rivers and lakes, which is then processed by large sluice boxes. The dredged fluid and material are passed over the sluice box classifier screens to separate the heavier solids from lighter solid material. Some classifier devices have ribbed constructions within the sluice box to capture the smaller relatively heavy particles.
U.S. Pat. No. 1,637,625, issued to E. Shaw, discloses another type of device that is used to clean and classify sand particles. The device uses a series of chambers to collect various sized particles.
Notwithstanding the current art, it remains clear that there is a need for a lightweight device that can be used by an individual to separate and capture the heavier desirable solid materials from lighter materials. In addition, the larger sluice boxes frequently are inefficient and fail to capture much of the heavier material, permitting that material to be washed through the sluice box to be lost as a part of the outflow. Therefore, it also remains clear that there is a need for an efficient device that can be used in conjunction with existing sluices and dredges to refine and separate the desirable material from the outflow of those dredges and sluice boxes.